1. Field of the Invention
The invention relates to a fluid injector and a method of manufacturing the same; in particular, a fluid injector with enhanced efficiency and lifetime.
2. Description of the Related Art
Normally, a fluid injector is applied in an inkjet printer, a fuel injector, and other devices. Among inkjet printers presently known and used, injection by a thermally driven bubble has been most successful due to its simplicity and relatively low cost.
FIG. 1 is a conventional monolithic fluid injector 1 as disclosed in U.S. Pat. No. 6,102,530. A structural layer 12 is formed on a silicon substrate 10. A fluid chamber 14 is formed between the silicon substrate 10 and the structural layer 12 to receive fluid 26. A first heater 20 and a second heater 22 are disposed on the structural layer 12. The first heater 20 generates a first bubble 30 in the chamber 14, and the second heater 22 generates a second bubble 32 in the chamber 14 to eject the fluid 26 from the chamber 14.
The monolithic fluid injector 1 includes a virtual valve, and is arranged in high-density. Furthermore, the monolithic fluid injector 1 exhibits low intermixing and low heat-loss. In addition, there is no need to connect an additional nozzle plate with the monolithic fluid injector. As a result, the cost of the monolithic fluid injector 1 can be lower.
However, in the conventional monolithic fluid injector 1, the structural layer 12 mainly consists of silicon oxide with low stress. During manufacture, the thickness of the structural layer 12 is kept within a predetermined range; therefore, the lifetime of the whole structure of the conventional monolithic fluid injector 1 is also limited. Furthermore, since the thickness of the structure layer 12 is insufficient, the injection direction of injecting fluid cannot be consistent. In addition, since the heaters 20, 22 are located on the structural layer 12, most of the heat generated by the heaters 20, 22 can be conducted to the fluid 26 in the chamber 14. However, some of the residual heat generated by the heaters 20, 22 remains and accumulates in the structural layer 12, and operation of the whole system is affected.